The present application finds particular application in vehicle speed sensor systems, particularly involving wheel speed sensor systems. However, it will be appreciated that the described techniques may also find application in other diagnostic systems, other vehicle monitoring systems, or other troubleshooting systems.
Some conventional wheel speed sensors are positioned proximate to an exciter ring. The wheel speed sensor is generally not fixed within its mounting location so that the wheel speed sensor position can be adjusted throughout the life of the wheel speed sensor to maintain an airgap between the exciter ring and wheel speed sensor surface, thereby mitigating damage due to wheel end wobble, for example. The wheel speed sensor generates an alternating voltage signal as the exciter ring passes the surface of the sensor. If an airgap between the sensor and the exciter ring is too large, the ABS unit cannot function and faults, and large airgaps cannot be detected until the ABS unit is no longer capable of reading the sensor signal. Another problem with conventional systems arises when an airgap between the sensor and the exciter ring is within acceptable tolerances at the factory but comes out of tolerance within a few miles of driving. This results in unnecessary warranty returns and the like, when in fact there is nothing wrong with the wheel speed sensor itself.
The present innovation provides new and improved systems and methods that facilitate detecting unacceptably large airgaps between wheel speed sensors and their exciter rings, which overcome the above-referenced problems and others.